This invention relates to drive apparatus for an irrigation line, and more particularly, to a drive apparatus including brake means and control means for providing that the movement of such irrigation line is properly controlled.
U.S. Pat. No. 3,952,952 discloses a braking system for an air-powered sprinkler system. In such apparatus, a brake is mounted on a drive tower and is urged into direct engagement with the inside of a drive wheel rim. Such actuation takes place through the pressurization of an air cylinder. It is to be understood that, with the tremendous amount of weight and momentum of a moving system of the type disclosed in U.S. Pat. No. 3,952,952, including the consideration that the water supply pipe itself carries a great weight of water, an extremely large braking force is required to stop movement of such system.
Of more general interest in this area are U.S. Pat. No. 3,386,661, U.S. Pat. No. 3,606,161, U.S. Pat. No. 3,690,343, U.S. Pat. No. 3,766,937, and U.S. Pat. No. 3,886,836, each of which discloses an irrigation system transportable through reciprocation of a bar which engages with flanges on the outer periphery of the support wheels.
In the overall control of movement of an irrigation line, it is also important that the line be kept in substantial alignment during the operation thereof, i.e., that one part not be allowed to run ahead of or fall behind other parts thereof. In this direction, it is well known to provide an irrigation line made up of a plurality of sections connected by flexible couplings, and to provide means for providing more or less driving torque to the wheels of a particular tower as that tower lags behind or leads other towers in movement. Such a system is generally disclosed in U.S. Pat. No. 2,604,359 to Zyback. It would highly advantageous to provide such a system wherein braking means of the type described above further provide control of overall movement of the system.